1. Field of the Invention
The present invention relates to a golf swing-measuring system and more particularly to a system of automatically and accurately extracting the movement of golfer's joints and the like from images in which the golfer's swing is photographed.
2. Background Art
There are proposed various kinds of apparatuses for photographing a golfer's swing, automatically computing information such as a flight distance, orbit, and the like of a hit golf ball by a computer, and displaying the obtained information for a golfer. These apparatuses allow the golfer to examine the flight distance, orbit, and the like of the hit ball. However, these apparatuses are incapable of providing information useful for improving the golfer's swing form.
In the swing form diagnosis apparatus disclosed in Japanese Patent Application Laid-Open No. 2003-117045, a golfer's swing is photographed to extract images of only specific motion points important for diagnosing the swing form. More specifically, frames regarding the golfer's swing motion are extracted from the golfer's moving image photographed by the photographing means. Specific motion points during the swing motion are judged according to results of analysis of the moving partial images in the differential image between each frame and the reference image. A frame corresponding to each of the specific motion points is extracted to display the image.
However, even though a frame corresponding to each specific motion point during the swing motion is extracted, it is impossible to provide the golfer with the motion of the joints and the like during the swing by merely looking at an extracted image. Therefore it is difficult for the golfer to find defects in her/his swing form and points to be corrected.
In the motion diagnosis apparatus disclosed in U.S. Pat. No. 2,794,018, a plurality of motion points are mounted on a golf club head and a person whose swing is to be diagnosed to obtain the coordinates of the motion points in a swing moving image. Thereby the swing is diagnosed. But it is necessary to perform computations for extracting the coordinates of a large number of motion points for all frames of the swing moving image. Therefore the amount of computation is very large, and the coordinate of the position of each of the motion points is erroneously recognized to a high extent. Further there is a case in which the motion point is hidden with the golfer's arm and the like while the golfer is swinging. In this case, a camera is incapable of recognizing the motion points. Consequently it is impossible to obtain the coordinate of the position of each of the motion points. Thus there is a high probability that the swing is erroneously diagnosed.
In the above-described motion diagnosis apparatus, it is impossible to grasp the golfer's body motion in an image unless the motion points such as marks are mounted on a user's body. Thus the user has a troublesome preparatory work in diagnosing her/his swing. In addition, it is necessary to perform computations for extracting the coordinates of a large number of the motion points for all frames of the swing moving image. Therefore the amount of computation is very large, and the coordinates of the positions of the motion points are erroneously recognized to a high extent.
Patent document 1: Japanese Patent Application Laid-Open No. 2003-117045
Patent document 2: Patent No. 2794018